Piezoelectric composites are being developed for use as active materials in isolation mounts. The ability to sense and respond to both longitudinal and shear waves is required. Composites have been fabricated with piezoelectric rods at different angles with respect to the surface. The response of the piezoelectric rods to a sharp impulse on the 1 - 3 composite plate increases abruptly at angles less than 60 degrees from the surface of the plate. Angled rods aligned radially are more sensitive then similarly angled rods aligned normal to the signal source. Mechanical impact and embedded acoustic generators at the center of the composite produced the signals for the sensitivity experiments. Oriented piezoelectric ceramic elements allow design of materials for specific mode control and also provide an excellent tool for in-situ nondestructive testing of materials.
H. Dean Batha,
"Effect of piezoelectric rod orientation on optimum sensitivity", Proc. SPIE 1916, Smart Structures and Materials 1993: Smart Materials, (23 July 1993); doi: 10.1117/12.148485; https://doi.org/10.1117/12.148485